package net.paoding.analysis.demo;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Date;

import net.paoding.analysis.analyzer.PaodingAnalyzer;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.LongField;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

public class ChineseIndex {
    private static String FIELD_NAME = "contents";

    public static void main(String[] args) throws Exception {

        String indexPath = "index";
        String docsPath = "docs";
        boolean create = true;

        // 将庖丁封装成符合Lucene要求的Analyzer规范
        Analyzer analyzer = new PaodingAnalyzer();

        //接下来是标准的Lucene建立索引和检索的代码
        Date start = new Date();
        File docDir = new File(docsPath);
        System.out.println("doc path : " + docDir.getAbsolutePath());
        if (!docDir.exists() || !docDir.canRead()) {
            System.out.println("Document directory '" + docDir.getAbsolutePath()
                    + "' does not exist or is not readable, please check the path");
            System.exit(1);
        }
        File indexFile = new File(indexPath);
        System.out.println("Indexing to directory '" + indexFile.getAbsolutePath() + "'...");

        Directory dir = FSDirectory.open(indexFile);
        IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_44, analyzer);

        if (create) {
            // Create a new index in the directory, removing any
            // previously indexed documents:
            iwc.setOpenMode(OpenMode.CREATE);
        } else {
            // Add new documents to an existing index:
            iwc.setOpenMode(OpenMode.CREATE_OR_APPEND);
        }

        IndexWriter writer = new IndexWriter(dir, iwc);
        indexDocs(writer, docDir);

        writer.close();

        Date end = new Date();
        System.out.println(String.format("索引完成，共耗时 %s  -ms. ", end.getTime() - start.getTime()));
    }

    static void indexDocs(IndexWriter writer, File file) throws IOException {
        // do not try to index files that cannot be read
        if (file.canRead()) {
            if (file.isDirectory()) {
                String[] files = file.list();
                // an IO error could occur
                if (files != null) {
                    for (int i = 0; i < files.length; i++) {
                        indexDocs(writer, new File(file, files[i]));
                    }
                }
            } else {

                FileInputStream fis;
                try {
                    fis = new FileInputStream(file);
                } catch (FileNotFoundException fnfe) {
                    // at least on windows, some temporary files raise this exception with an "access denied" message
                    // checking if the file can be read doesn't help
                    return;
                }

                try {

                    // make a new, empty document
                    Document doc = new Document();

                    // Add the path of the file as a field named "path".  Use a
                    // field that is indexed (i.e. searchable), but don't tokenize 
                    // the field into separate words and don't index term frequency
                    // or positional information:
                    Field pathField = new StringField("path", file.getPath(), Field.Store.YES);
                    doc.add(pathField);

                    // Add the last modified date of the file a field named "modified".
                    // Use a LongField that is indexed (i.e. efficiently filterable with
                    // NumericRangeFilter).  This indexes to milli-second resolution, which
                    // is often too fine.  You could instead create a number based on
                    // year/month/day/hour/minutes/seconds, down the resolution you require.
                    // For example the long value 2011021714 would mean
                    // February 17, 2011, 2-3 PM.
                    doc.add(new LongField("modified", file.lastModified(), Field.Store.NO));

                    // Add the contents of the file to a field named "contents".  Specify a Reader,
                    // so that the text of the file is tokenized and indexed, but not stored.
                    // Note that FileReader expects the file to be in UTF-8 encoding.
                    // If that's not the case searching for special characters will fail.
                    doc.add(new TextField(FIELD_NAME, new BufferedReader(new InputStreamReader(fis,
                            "UTF-8"))));

                    if (writer.getConfig().getOpenMode() == OpenMode.CREATE) {
                        // New index, so we just add the document (no old document can be there):
                        System.out.println("adding " + file);
                        writer.addDocument(doc);
                    } else {
                        // Existing index (an old copy of this document may have been indexed) so 
                        // we use updateDocument instead to replace the old one matching the exact 
                        // path, if present:
                        System.out.println("updating " + file);
                        writer.updateDocument(new Term("path", file.getPath()), doc);
                    }

                } finally {
                    fis.close();
                }
            }
        }
    }
}
